In the quest for future post-CMOS devices, many transistors have been proposed in the past decade. For example, tunnel field-effect transistors (“TFETs”), such as symmetric graphene-insulator-graphene TFETs (known as SymFETs), have some characteristics similar to those of MOSFETs and some that are different from MOSFETs. Accordingly, the inventors of this disclosure have appreciated that the particular characteristics of TFETs enable TFETs to be implemented in particular circuits to offer advantages over CMOS-based circuits.